By disambiguating it from being set to rhuk_solarflare_ii, it means it will grab the appropriate styles from the relevant template and then style with offline.css. It also deals with the XML prolog issue that's been affecting frontend and backend rendering via quirks mode.

As a final note on this one, I changed the css file to offline.css as there were style conflicts with using template_css.css. So, now the offline.php will include templates/css/offline.css and if present, templates/$current_template/css/offline.css

RobS wrote:
As a final note on this one, I changed the css file to offline.css as there were style conflicts with using template_css.css. So, now the offline.php will include templates/css/offline.css and if present, templates/$current_template/css/offline.css

Probably not the best path to take.. CSS allows precedence and if you want your 'offline' status styled in the same way as your 'online' templates, the only problem therefore will be potential malformedness on part of the initial offline.css file / offline template design.

So it's not the template_css.css file at fault, but the way the offline effect is delivered.